Warm up waistcoat



FIG. 1 is a front view of a warm up waistcoat showing my new design;

FIG. 2 is a rear-opened view thereof; and,

FIG. 3 is a partial side view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a warm up waistcoat, as shown and described. 